Atomic Structure

Atomic Structure

In 1805 John Dalton published his atomic theory that said: 

• all matter is made up of tiny particles called atoms
• atoms cannot be created or destroyed
  
• atoms cannot be broken down into smaller parts
• the atoms in an element are identical
• during chemical reactions atoms rearrange to make different substances

In 1897 JJ thomson discovered electrons. He modeled the atom as a 'plum pudding'- a ball of positive charge with negatively charged electrons.

In 1909, Rutherford discovered that alpha particles could bounce back off atoms. From this it was concluded that an atom's mass was concluded in the centre. This was called the nucleus and it contained positively charged atoms called protons.- the nuclear model

Neils Bohr discovered that electrons orbit the nucleus, in 1932 James Chadwick discovered that some particles in the nucleus have no charge at all (neutrons)…